2 files changed, 40 insertions, 16 deletions

diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c
index c8bab24ff8ac..10b681c092ed 100644
--- a/arch/powerpc/kernel/kvm.c
+++ b/arch/powerpc/kernel/kvm.c
@@ -42,6 +42,7 @@
 #define KVM_INST_B_MAX          0x01ffffff
 
 #define KVM_MASK_RT             0x03e00000
+#define KVM_RT_30               0x03c00000
 #define KVM_MASK_RB             0x0000f800
 #define KVM_INST_MFMSR          0x7c0000a6
 #define KVM_INST_MFSPR_SPRG0    0x7c1042a6
@@ -82,6 +83,15 @@ static inline void kvm_patch_ins(u32 *inst, u32 new_inst)
         flush_icache_range((ulong)inst, (ulong)inst + 4);
 }
 
+static void kvm_patch_ins_ll(u32 *inst, long addr, u32 rt)
+{
+#ifdef CONFIG_64BIT
+        kvm_patch_ins(inst, KVM_INST_LD | rt | (addr & 0x0000fffc));
+#else
+        kvm_patch_ins(inst, KVM_INST_LWZ | rt | (addr & 0x0000fffc));
+#endif
+}
+
 static void kvm_patch_ins_ld(u32 *inst, long addr, u32 rt)
 {
 #ifdef CONFIG_64BIT
@@ -186,7 +196,6 @@ static void kvm_patch_ins_mtmsrd(u32 *inst, u32 rt)
 extern u32 kvm_emulate_mtmsr_branch_offs;
 extern u32 kvm_emulate_mtmsr_reg1_offs;
 extern u32 kvm_emulate_mtmsr_reg2_offs;
-extern u32 kvm_emulate_mtmsr_reg3_offs;
 extern u32 kvm_emulate_mtmsr_orig_ins_offs;
 extern u32 kvm_emulate_mtmsr_len;
 extern u32 kvm_emulate_mtmsr[];
@@ -216,9 +225,27 @@ static void kvm_patch_ins_mtmsr(u32 *inst, u32 rt)
         /* Modify the chunk to fit the invocation */
         memcpy(p, kvm_emulate_mtmsr, kvm_emulate_mtmsr_len * 4);
         p[kvm_emulate_mtmsr_branch_offs] |= distance_end & KVM_INST_B_MASK;
-        p[kvm_emulate_mtmsr_reg1_offs] |= rt;
-        p[kvm_emulate_mtmsr_reg2_offs] |= rt;
-        p[kvm_emulate_mtmsr_reg3_offs] |= rt;
+
+        /* Make clobbered registers work too */
+        switch (get_rt(rt)) {
+        case 30:
+                kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg1_offs],
+                                 magic_var(scratch2), KVM_RT_30);
+                kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg2_offs],
+                                 magic_var(scratch2), KVM_RT_30);
+                break;
+        case 31:
+                kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg1_offs],
+                                 magic_var(scratch1), KVM_RT_30);
+                kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg2_offs],
+                                 magic_var(scratch1), KVM_RT_30);
+                break;
+        default:
+                p[kvm_emulate_mtmsr_reg1_offs] |= rt;
+                p[kvm_emulate_mtmsr_reg2_offs] |= rt;
+                break;
+        }
+
         p[kvm_emulate_mtmsr_orig_ins_offs] = *inst;
         flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtmsr_len * 4);
 
@@ -402,9 +429,7 @@ static void kvm_check_ins(u32 *inst, u32 features)
                 break;
         case KVM_INST_MTMSR:
         case KVM_INST_MTMSRD_L0:
-                /* We use r30 and r31 during the hook */
-                if (get_rt(inst_rt) < 30)
-                        kvm_patch_ins_mtmsr(inst, inst_rt);
+                kvm_patch_ins_mtmsr(inst, inst_rt);
                 break;
         }
 
diff --git a/arch/powerpc/kernel/kvm_emul.S b/arch/powerpc/kernel/kvm_emul.S
index a6e97e7a55e0..65305325250b 100644
--- a/arch/powerpc/kernel/kvm_emul.S
+++ b/arch/powerpc/kernel/kvm_emul.S
@@ -135,7 +135,8 @@ kvm_emulate_mtmsr:
 
         /* Find the changed bits between old and new MSR */
 kvm_emulate_mtmsr_reg1:
-        xor     r31, r0, r31
+        ori     r30, r0, 0
+        xor     r31, r30, r31
 
         /* Check if we need to really do mtmsr */
         LOAD_REG_IMMEDIATE(r30, MSR_CRITICAL_BITS)
@@ -156,14 +157,17 @@ kvm_emulate_mtmsr_orig_ins:
 
 maybe_stay_in_guest:
 
+        /* Get the target register in r30 */
+kvm_emulate_mtmsr_reg2:
+        ori     r30, r0, 0
+
         /* Check if we have to fetch an interrupt */
         lwz     r31, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0)
         cmpwi   r31, 0
         beq+    no_mtmsr
 
         /* Check if we may trigger an interrupt */
-kvm_emulate_mtmsr_reg2:
-        andi.   r31, r0, MSR_EE
+        andi.   r31, r30, MSR_EE
         beq     no_mtmsr
 
         b       do_mtmsr
@@ -171,8 +175,7 @@ kvm_emulate_mtmsr_reg2:
 no_mtmsr:
 
         /* Put MSR into magic page because we don't call mtmsr */
-kvm_emulate_mtmsr_reg3:
-        STL64(r0, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
+        STL64(r30, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
 
         SCRATCH_RESTORE
 
@@ -193,10 +196,6 @@ kvm_emulate_mtmsr_reg1_offs:
 kvm_emulate_mtmsr_reg2_offs:
         .long (kvm_emulate_mtmsr_reg2 - kvm_emulate_mtmsr) / 4
 
-.global kvm_emulate_mtmsr_reg3_offs
-kvm_emulate_mtmsr_reg3_offs:
-        .long (kvm_emulate_mtmsr_reg3 - kvm_emulate_mtmsr) / 4
-
 .global kvm_emulate_mtmsr_orig_ins_offs
 kvm_emulate_mtmsr_orig_ins_offs:
         .long (kvm_emulate_mtmsr_orig_ins - kvm_emulate_mtmsr) / 4